Conventional spacers have a hollow body having a substantially square transverse cross-section. Generally, the body is provided with four holes, at its four corners, through which bolts are passed to mutually secure the members separated by the spacer. The holes are in the wall of the body and are not open to the central hollow portion or the exterior of the body.
Because the conventional spacer is usually made by die casting aluminum, the inner and outer surfaces of the body are tapered adding unnecessary weight to the center portion of the body. Additional unnecessary weight is present in conventional spacers in the form of protrusions inwardly extending from the inner surface of the walls of the body which are necessary to facilitate extraction of the body from the die.
Mass production makes the individual die casting of spacers impractical. A more efficient manner of mass producing spacers having identical cross-sections but different lengths is by extrusion. Conventional spacers however, are difficult to extrude because of their complicated cross-sectional structure. In particular, the four bolt holes are separated and independent from each other and the central hollow portion. Such a spacer having five individual hollow portions is difficult to make by extrusion because the pitch of each of the five hollow portions will vary during the extrusion process.
In order to mass produce spacers by the more efficient extrusion process, therefore, it is necessary to simplify the cross sectional structure of the spacers. The instant invention provides a spacer having a simplified cross section capable of being extruded, thereby permitting mass production of the spacers through extrusion and reducing the weight of the spacers by eliminating unnecessary structure.